Insert into 3 tables (pivot) from a form (Thank you)

Hello everyone and thank you in advance for your help,

I continue my learning of Laravel.

I have an "event" table, a "years" table and an event_years (pivot) table because an event can end up in several years and a year can have several events.

I would like to insert a new event via a form, for that I get what was encoded by the user.

Before, I had only one table, because an event was only in one year, so I had this code:

            'name' => 'required|string|max:255',
            'mnemonique' => 'required|string|max:255',
            'color' => 'required|string|max:255',
            'year_id' => 'required|integer'
        ]);

        $evenement = new Evenement();
        
        $evenement->create($validatedData);

I see that in the official Laravel documentation, we must go and retrieve the id, but here, I did not see any that it is a new event that did not exist:

Sample code:

$ user = App \ User :: find (1);

$ user-> roles () -> attach ($ roleId); 

How can I please do to insert the data into the 3 tables?

Here are my models:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Evenement extends Model
{
    protected $fillable = ['name', 'year_id','mnemonique','color'];
      
    public function years()
    {
        return $this->belongsToMany(Year::class, 'evenement_year','evenement_id','year_id'); 
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Year extends Model
{
    protected $fillable = ['name'];

    public function evenements()
    {
        return $this->belongsToMany(Evenement::class, 'evenement_year','year_id','evenement_id');
        
    }
}

Thank you for your help.